1. Field of the Invention
The present invention relates to a disc clamping apparatus. More particularly, the present invention relates to an automatic up-and-down disc clamping apparatus with magnets.
2. Description of the Prior Art
In 1997, the DVD Alliance published a DVD-RAM standard in which a disc with a cartridge is revealed. A thickness of the cartridge is about 8 mm. Interference between the cartridge and a disc clamp may occur while loading or ejecting the cartridge. Interference means that a position of the disc clamp is not high enough so that the disc clamp touches the cartridge during the loading or ejecting process. Damage to the cartridge may occur or data stored in the disc may even be lost.
Currently designs in disc clamping apparatus for disc players employ an elastic lever mechanism constructed in a chucking plate to lift up a disc clamp. Reference is made to FIGS. 1A and 1B, which illustrate schematic views of a prior art disc clamping apparatus and its operating movement. As shown in FIG. 1A, when a cartridge holder 10 of a disc player is moved in a loading state outside the disc player, an elastic lever mechanism 30 constructed in the chucking plate 20 begins to operate.
When a contact rod 32 of the elastic lever mechanism 30 is separated from the cartridge body 10, an elastic device 38 causes a lever rod 36 of the elastic lever mechanism 30 to rotate with a hinge point 34 as a pivot center such that a disc clamp 40 is lifted up. Therefore, interference between the disc clamp 40 and a cartridge is prevented.
Reference is made to FIG. 1B, in which the cartridge holder 10 is moved back into the disc player. When the cartridge holder 10 makes contact with the contact rod 32, the elastic device 38 is compressed. The lever rod 36 is rotated with the hinge point 34 as the pivot center such that the disc clamp 40 is lowered down and clamped onto a disc. Finally, a spindle motor (not shown) is lifted up. The disc is then supported by the spindle motor. At this moment, the disc is secured by the disc clamp 40 and the spindle motor. Rotation of the disc follows and data can be read or written on the rotating disc.
Unfortunately, the prior art elastic lever mechanism 30 has a lot of components. Its assembly is not easy. Moreover, the up-and-down motion of the elastic lever mechanism 30 requires a large operating space. All of these problems increase the complexity of a structural design for a disc player.